#2305 UFO flying rhumb line instead of great circle

UFO always flies a rhumb line as if it was always flying with heading hold, while one would normally expect an ideal airplane to fly:

• great circle when simply flying straight;
• rhumb line with heading hold.
  This is most noticeable when you are near the poles, as you start to side-slip a lot.

Of course UFO should not be expected to behave totally like a plane -- so I don't know how inconvenience this is for anyone else, but personally this makes these things unnecessarily hard:

• crash- and leak-hunting sessions with UFO flying for hours, because eventually it gets trapped in the poles, and you have to check on it from time to time and respawn;
• flying straight from A to B.

[eatdirt]

Since I flew it a lot recently, I confirm this and this is particularly annoying. You always have to compensate with the rudder when flying fast, and indeed, if you end up at the pole, it is actually quite hard to escape once locked in :)

[James Turner]

The UFO always files a constant heading, indeed. Keep in mind it doesn't have any notion of a centerline or mass, it's effectively /always/ in heading hold mode. So we'd need to do something clever near the poles to avoid it getting stuck.

[Anonymous]

Great circle is a constant heading, too, but with relation to a fixed meridian instead of the current one :)

I'm guessing that constant heading needs way fewer calculations, because it simply uses current heading wihout having to adjust for the effective "turning"?

[James Turner]

Well the UFO literally has a variable storing the current heading as a number, driven by joystick input. Each update it moves in that heading a set distance (based on speed). No movement (around the poles or whatever will ever modify the heading it's flying, only joystick input does that.